It is a fairly common practice for farmers having larger farms to plant more than one crop. In the midwest, a farmer may plant both corn and soybeans, and in western states, a farmer may plant corn and wheat. Typically, corn, being a larger crop, is planted at a row spacing of 30 inches. Soybeans are planted at ten, fifteen or thirty inch spacing, depending on the preferences and equipment of the farmer.
Since the planting season typically may include only ten days or so of good planting weather, it has become highly desirable to minimize the amount of time necessary to convert a planter from one crop to another. Of course, the farmer could buy and have prepared separate planters, but that would be unreasonably expensive. One solution to the problem is to provide a tandem planter--that is, two identical planters, one pulled behind the other, with the row units of the two planters being offset so that the row units on the rear planter are located to form furrow midway between the furrows formed on the forward planter. Such inter-row planter units are sometimes referred to as "interplant" units. Attempts have been made to make such planters rigid so that the placement of the interplant rows relative to the forward rows is fixed. However, such arrangements of tandem planters are expensive and have a considerable length such that they become unwieldy in making critical field maneuvers and in transport.
Another attempt to provide interplant row units simply mounts the interplant units on the same mounting bar as the regular units so that the mounting of units is side-by-side across the planter frame. This is possible and enables the achievement of 15" rows because commercial row units of a desirable type having double disc furrow openers and adjacent gauge wheels are available and they have a nominal width of approximately 15", leaving 15" between adjacent row units mounted to plant rows spaced at 30". There are two disadvantages with such a side-by-side arrangement. First, commercially available row units typically have a seed hopper mounted in a forward position above the furrow opener and a separate rear hopper for storing insecticide or herbicide which is deposited behind the furrow opener after the seed is deposited and the furrow is closed. These hoppers have to be replenished with seed and fertilizer/insecticide at least twice a day if the planter is used for a full day's planting. It is difficult for the farmer to take the lids off the hoppers when the row units are place immediately adjacent one another, and it is also difficult for the farmer to maneuver a 50-55 lb. bag of seed to replenish the forward hopper without spilling some of the seed. Moreover, it has been found in practice that when row units are mounted on a common bar in side-by-side relation, the adjacent gauge wheels of adjacent units are very close to one another and provide a natural trap for unbroken clods of soil or trash such as corn stalks or remaining unburied crop. This latter problem has become exacerbated with modern conservation planting techniques which leave more and more trash on the surface of the soil.
Moreover, from a manufacturer's standpoint, when row units are placed on a common mounting bar in side-by-side relation with the row units immediately adjacent one another, special arrangements have to be made to secure the planter support wheels to the frame. Normally, such support wheels are located between adjacent row units if the row units are spaced apart by 30" as they typically have been prior to inserting interplant row units between the normally spaced units.
In all such arrangements, the individual row units are mounted to one or more transverse mounting bars which are part of the planter frame by means of four-bar linkages which enable the row units individually to accomodate themselves to variations in ground contour. This is highly desirable because it is generally recognized that the depth of the furrow in which the seed is deposited is, particularly in the case of certain crops, a critical factor in determining the early and uniform emergence of the crop.
A more desirable and practical solution to the problem of providing a row crop planter which is easily convertible to different row spacings, as described in my above-identified co-pending application, is to provide the interplant row units in front of the planter frame so that they are pushed or driven by the planter frame during normal operation. This arrangement leaves adequate space between adjacent row units for access to the hoppers for replenishing the commodity in the hopper, and it also avoids the above-described problem of plugging the space between adjacent gauge wheels when row units are placed on a common mounting bar and immediately adjacent one another. Morevoer, I have found that the push-type row units can be mounted to the planter frame by means of four-bar linkages so that they individually can accomodate changes in ground contour.
However, the arrangement disclosed in my co-pending application is not capable of achieving a row space less than 15" if the rear or pull-type units are mounted at the desired 30" spacing for corn. In other words, because it is highly desirable to plant corn at a 30" row spacing since any lesser spacing is perceived as having a diminishing effect on yield, the rear row units of that arrangement are mounted at a 30" spacing, and the push-type row units are mounted at a similar spacing, and they are centered on the space between the rear units. Thus, when all row urits are used, the row spacing achieved is 15".
Such an arrangement is quickly and easily converted between either the wide or narrow row spacing by locking the forward row units in a raised position for the wide spacing and lowering them to the use position for the narrow spacing. In this arrangement, the rear row units are mounted to a rear mounting bar on the planter frame and a separate forward mounting bar is provided for the forward row units, with the support wheels being mounted between the forward and rear mounting bars. This configuration has been found to be very useful and has been commercially successful in that substantial numbers of planters in this configuration have been sold. Howeeer, because of the desirability of planting corn at a row spacing of no less than 30", such a configuration is not capable of achieving a row spacing less than 15" unless row units are placed immediately side-by-side on both the forward and rear mounting bars. Although such an arrangement is possible, it presents both of the aforementioned problems of (1) inconvenience in loading hoppers, and (2) plugging between adjacent gauge wheels for both the pull-type row units and the push-type row units, since the push-type row units also employ the opener type which has twin-disc furrow openers and adjacent gauge wheels.
The present invention provides improvements to the planter disclosed in my co-pending application. According to the present invention, a plurality of conventional pull-type units are mounted to a mounting bar on a planter frame at a 30" row spacing for corn, thereby leaving room between adjacent row units for access to the hoppers for filling. Similarly, push-type row units are mounted to the planter frame in front of a mounting bar at the same nominal spacing, and the push-type row units disclosed herein are preferrably, though not necessarily mounted to the same mounting bar, thereby reducing the cost of the planter frame and reducing the overall length of the planter. The planter support wheels are mounted between adjacent row units behind the mounting bar.
Moreover, the push-type row units are modified to include two separate planting mechanisms, each planting mechanism including a furrow opener and closer; and, in the illustrated embodiment, each planting mechanism has its own metering device, but they share a common hopper and frame. The spacing of the planting mechanisms on the forward row units is 10".
The planting mechanisms on the forward row units are located relative to the rear row units to achieve an overall row spacing of 10" when the forward row units are used.
Thus, the present invention provides a row crop planter which is readily convertible between a narrow row spacing and a wide row spacing without having to remove or add or relocate individual row units, but the present invention is capable of achieving a row spacing of 10" without the aforementioned problems of plugging and while providing convenient access to the row unit hoppers for filling. Thus, the present invention is capable of planting wheat as well as soybeans, it being desirable on the part of some farmers to plant soybeans at a 10" spacing, and it being a common practice to plant wheat, when it is planted in rows, at a spacing of 10".
Thus, the present invention provides a convertible planter which has a wide adaptability and is readily convertible, yet which is more economical from the standpoint of the cost of the planter frame.
Other features and advantages of the present invention will be apparent to persons skilled in the art from the following detailed description of a preferred embodiment accompanied by the attached drawing wherein identical reference numerals will refer to like parts in the various views.